JPH06303095A - Microwave phase shifter - Google Patents

Abstract

PURPOSE:To vary phase forwarded amounts or phase delayed amounts against the microwave signals of a microwave phase shifter. CONSTITUTION:This device is constituted of a low pass filter 60 connected between a first output terminal 11 of a first single electrode double-throw switch 2 and a first input terminal 31 of a second single electrode double throw switch 4, and a high pass filter 70 connected between a second output terminal 12 of the first low pass filter and a second input terminal 32 of the second single electrode double throw switch. Then, dual gates FET 63 and 73 are used as each capacitance element in the low pass filter and the high pass filter, a bias voltage sufficient for maintaining the dual gate FET in a pinch off state is impressed to one gate electrode, and the bias voltage sufficient for obtaining a required capacitance value is impressed to the other gate electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dual gate field effect transistor (hereinafter referred to as a dual gate FET) as a capacitance element or an equivalent semiconductor element,
For example, the present invention relates to a microwave phase shifter in which the amount of advanced phase or the amount of delayed phase is variable by using two single gate field effect transistors connected in series.

[0002]

2. Description of the Related Art FIG. 4 is an equivalent circuit diagram showing a structure of a conventional microwave phase shifter. In the figure, 2 is a first single-pole double-throw switch on the input side, 4 is a second single-pole double-throw switch on the output side, and the input terminal 3 of the first single-pole double-throw switch 2 has, for example, a microstrip line. A microwave signal is supplied via an input line 13 composed of the following, and an output terminal 5 of the second single-pole double-throw switch 4 is connected to an output line 15 composed of, for example, a microstrip line.

The first single-pole double-throw switch 2 is provided with a first output terminal 11 and a second output terminal 12, and between the input terminal 6 and the first output terminal 11, the input terminal 6 is provided. And the second
For example, N-channel FETs 16 and 18 are connected in series between the output terminal 12 and the output terminal 12, respectively. An N-channel FET 17 is connected between the first output terminal 11 and the ground potential point, and an N-channel FET 19 is connected between the second output terminal 12 and the ground potential point. The gate electrodes of the FETs 16 and 19 pass through resistors 26 and 29, respectively, and one switching signal input terminal 2
The gate electrodes of the FETs 17 and 18 are connected to the other switching signal input terminal 22 via resistors 27 and 29, respectively.

The second single-pole double-throw switch 4 is provided with a first input terminal 31 and a second input terminal 32.
Between the input terminal 31 and the output terminal 5 of the second input terminal 3
N-channel FET3 between 2 and the output terminal
6, 38 are connected in series. Further, an N-channel FET 37 is provided between the first input terminal 31 and the ground potential point.
However, the N-channel FET 49 is connected between the second input terminal 12 and the ground potential point. FET3
Gate electrodes 6 and 39 are connected to one switching signal input terminal 41 via resistors 46 and 49, respectively, and gate electrodes of FETs 47 and 48 are connected to resistor 4 respectively.
It is connected to the other switching signal input terminal 42 via 7, 49.

Between the first output terminal 11 of the first single-pole double-throw switch 2 and the first input terminal 31 of the second single-pole double-throw switch 4, an inductive element 5 connected in series is provided.
A low-pass filter 6 including 0, 51 and a capacitance element 52 connected between a connection point of both inductance elements and a ground potential point is connected. Between the second output terminal 12 of the first single-pole double-throw switch 2 and the second input terminal 32 of the second single-pole double-throw switch 4, there is a capacitance element 55, the output terminal 12 and the ground potential point. Between the input terminal 32 and the ground potential point is connected to the high-pass filter 7 including the inductance elements 43 and 54, respectively. The first single-pole double-throw switch 2, the second single-pole double-throw switch 4, the low-pass filter 6,
The high pass filter 7 is generally formed on one semiconductor substrate.

Next, the operation of the conventional microwave phase shifter shown in FIG. 4 will be described. One of the switching signal input terminals 21, 4
When the level of the switching signal supplied to 1 is L (low level) and the level of the switching signal supplied to the other switching signal input terminals 22 and 42 is H (high level), the first single-pole double-throw switch 2 FET16 is on, FET17 is off, FET18 is off, FET1
9 is turned on and the FET of the second single pole double throw switch 4
36 is on, FET 37 is off, FET 38 is off, F
ET39 turns on. At this time, the microwave signal supplied from the input line 13 to the input terminal 3 is supplied to the low-pass filter 6 via the FET 16 in the ON state, and the microwave signal delayed by the low-pass filter 6 is It is supplied from the first input terminal 31 of the 2-single-pole double-throw switch 4 to the output terminal 5 via the FET 36 in the ON state. The delayed microwave signal generated at the output terminal 5 is sent to the next stage via the output line 15 which is a microstrip line.

Assuming that the standardized reactance of the inductance elements 50 and 51 is X _N and the standardized susceptance of the capacitance element 52 is B _N , the inductance elements 50 and 51 and the capacitance element 5 are described.
The retardation amount θ ₁ in the low-pass filter 6 composed of 2 is represented by the following mathematical formula 1.

[0008]

[Equation 1]

One of the switching signal input terminals 21, 4
When the level of the switching signal supplied to 1 is H (high level) and the level of the switching signal supplied to the other switching signal input terminals 22 and 42 is L (low level), the first single-pole double-throw switch FET18 of 2 is ON, FET19 is OFF, FET16 is OFF, FET1
7 is turned on and the FET of the second single pole double throw switch 4
38 is on, FET 39 is off, FET 36 is off, F
ET37 turns on. At this time, the microwave signal supplied from the input line 13 to the input terminal 3 is supplied to the high-pass filter 7 via the FET 18 in the ON state, and the signal advanced by the high-pass filter 7 is the second signal. FET in the ON state from the second input terminal 32 of the pole double throw switch 4
It is supplied to the output terminal 5 via 38. The advanced microwave signal generated at the output terminal 5 is sent to the next stage via the output line 15.

Assuming that the standardized susceptance of the inductance elements 53 and 54 is B _N and the standardized reactance of the capacitance element 55 is X _N , the capacitance element 55 and the inductance shunt element 5 are shown.
Phase advance amount θ in the high-pass filter 7 composed of 3 and 54
₂ is represented by the following mathematical formula 2.

[0011]

[Equation 2]

As described above, in the circuit of FIG. 4, the first single-pole double-throw switch 2 and the second single-pole double-throw switch 4 are switched to the switching signal input terminals 21, 21, 41, 42 respectively. By switching according to the signal and selecting either the low-pass filter 6 or the high-pass filter 7, it operates as a high-pass / low-pass phase shifter for the microwave signal.

[0013]

In the conventional microwave phase shifter as described above, the values of the capacitance elements 52 and 55 in the low pass filter 6 and the high pass filter 7 are fixed. There was a problem that the amount of phase shift could not be made variable. An object of the present invention is to solve the problems of the conventional phase shifter and to obtain a microwave phase shifter capable of varying the amount of phase shift of the microwave signal.

[0014]

A microwave phase shifter according to a first invention of the present application comprises first and second inductance elements connected in series between a signal input terminal and a signal output terminal, It is configured by a low pass filter including a dual gate FET connected between an interconnection point of the first inductance element and the second inductance element and a reference potential point. A bias voltage large enough to maintain the dual gate FET in a pinch-off state is supplied to one gate electrode of the dual gate FET,
The other gate electrode is supplied with a bias voltage of a magnitude necessary for obtaining a capacitance value of a required magnitude in this dual gate FET.

A microwave phase shifter according to a second invention of the present application is a dual gate FET connected between a signal input terminal and a signal output terminal, and the above-mentioned signal input terminal and a reference potential point. The high pass filter is composed of first and second inductance elements connected between the signal output terminal and the reference potential point. A bias voltage of a sufficient magnitude to maintain the dual gate FET in a pinch-off state is supplied to one gate electrode of the dual gate FET, and the other gate electrode has a capacitance of a required magnitude in the dual gate FET. A bias voltage of the magnitude necessary to obtain the value is supplied.

A microwave phase shifter according to a third invention of the present application is a first single-pole double-throw switch having a signal input terminal and first and second output terminals, a signal output terminal, a first and a second output terminal. A second single pole double throw switch having a second input terminal, and a first output terminal of the first single pole double throw switch and a first input terminal of the second single pole double throw switch. A connected low pass filter and a high pass filter connected between the second output terminal of the first single pole double throw switch and the second input terminal of the second single pole double throw switch. Become. The low-pass filter includes first and second inductance elements connected in series between the first output terminal and the first input terminal, an interconnection point between the inductance elements, and a reference potential point. And a high-pass filter connected between the second output terminal and the second input terminal.
And between the second output terminal and the reference potential point, the second
Of the first and second inductance elements respectively connected between the input terminal and the reference potential point. A bias voltage large enough to maintain the dual gate FET in a pinch-off state at all times is supplied to one gate electrode of each dual gate FET, and the other gate electrode is required by these dual gate FETs. A bias voltage is provided as large as necessary to obtain a large capacitance value.

[0017]

In any of the inventions of the present application, since the capacitance value in each filter circuit can be adjusted by changing the bias voltage supplied to the second gate electrode of the dual gate FET, the low-pass filter can be adjusted. It is possible to adjust the amount of phase shift for the microwave signal by adjusting the amount of phase delay due to and the amount of phase advance due to the high pass filter.

[0018]

1 is an equivalent circuit diagram of a first embodiment of a microwave phase shifter of the present invention. In the figure, the first input side
Single-pole double-throw switch 2, second single-pole double-throw switch 4 on the output side
Is the same as that of the conventional microwave phase shifter shown in FIG. 4 in terms of its configuration and operation, and therefore, the same reference numerals as those in FIG.
A description of them will be omitted. Between the first output terminal 11 of the first single-pole double-throw switch 2 and the first input terminal 31 of the second single-pole double-throw switch 4, inductance elements 61 and 62 connected in series, and both A low-pass filter 60 including a dual gate FET 63 acting as a capacitance element connected in a source-grounded manner is connected between a connection point of the inductance element and a reference potential point, for example, a ground potential point. Also, the first single-pole double-throw switch 2
Second output terminal 12 of the second single pole double throw switch 4 of the second
Between the input terminal 32 of the output terminal 1 and the dual gate FET 73 which acts as a capacitance element.
2 and a reference potential point, for example, a ground potential point, and a high-pass filter 70 including inductance elements 71, 72 connected between the input terminal 32 and the reference potential point, for example, a ground potential point. Has been done. Similar to the conventional microwave phase shifter of FIG. 4, the first single-pole double-throw switch 2, the second single-pole double-throw switch 4, the low-pass filter 60,
The high pass filter 70 is generally formed on a single semiconductor substrate.

Next, the operation of the microwave phase shifter of the present invention shown in FIG. 1 will be described. To one of the gate electrodes of the dual gate FETs 63 and 73, for example, the first gate electrodes 64 and 74, a voltage large enough to keep the dual gate FETs 63 and 73 always in the pinch-off state is applied. A bias voltage of a magnitude necessary to obtain a capacitance value of a predetermined magnitude is applied to the two gate electrodes 65 and 75. FIG. 3 is a diagram showing how the dual gate FET acts on a bias voltage applied to each gate electrode of the dual gate FET.
(A) Dual gate FET first gate electrode, second
When a bias voltage of a magnitude that turns on the dual gate FET is applied to the gate electrode, the dual gate FET acts as a pure resistance as shown in FIG. 3B, and at least one of the gate electrodes has the dual gate. When a bias voltage large enough to pinch off the FET is applied, the dual gate FET will be
It operates as the capacitance element shown in any one of (c), (d), and (e). Dual gate FETs 63, 7 in each filter used in the microwave phase shifter of the present invention.
3 is biased to operate in any of the states shown in FIGS. 3C, 3D, and 3E.

Similar to the conventional microwave phase shifter shown in FIG. 4, the level of the switching signal supplied to one of the switching signal input terminals 21 and 41 is L (low level),
When the level of the switching signal supplied to the other switching signal input terminals 22 and 42 is H (high level), the FET 16 of the first single-pole double-throw switch 2 is turned on and FE
T17 is off, FET18 is off, FET19 is on, and FET36 of the second single-pole double-throw switch 4 is on, FET37 is off, FET38 is off, and FET39.
Turns on. At this time, the microwave signal supplied to the input terminal 3 via the input line 13 composed of the microstrip line is supplied to the low-pass filter 60 acting as a phase retarder via the FET 16 in the ON state, and the low-pass filter 60 is supplied. The signal delayed by 60 is the second single-pole double-throw switch 4
Is supplied from the first input terminal 31 to the output terminal 5 via the FET 36 in the ON state. The delayed microwave signal generated at the output terminal 5 is sent to the next stage via the output line 15 which is a microstrip line.

Here, the standardized reactance of the inductance elements 61 and 62 is X _N , and the dual gate FE
Letting B _N be the standardized susceptance of the capacitance element given by the off capacitance of T63, the amount of phase retardation θ ₃ in the low-pass filter 60 composed of the inductance elements 61 and 62 and the dual gate FET acting as a capacitance element. Is expressed by Equation 3 below.

[0022]

[Equation 3]

One of the switching signal input terminals 21, 4
When the level of the switching signal supplied to 1 is H (high level) and the level of the switching signal supplied to the other switching signal input terminals 22 and 42 is L (low level), the first single-pole double-throw switch FET18 of 2 is ON, FET19 is OFF, FET16 is OFF, FET1
7 is turned on and the FET of the second single pole double throw switch 4
38 is on, FET 39 is off, FET 36 is off, F
ET37 turns on. At this time, the microwave signal supplied from the input line 13 to the input terminal 3 passes through the FET 18 in the ON state, and the high-pass filter 7 acting as a phase advancer.
The signal supplied to 0 and advanced in the high-pass filter 70 is supplied to the output terminal 5 from the second input terminal 32 of the second single-pole double-throw switch 4 via the FET 38 in the ON state. The advanced microwave signal generated at the output terminal 5 is sent to the next stage via the output line 15.

Here, the standardized susceptance of the inductance elements 71 and 72 is B _N , the dual gate FE
When the standardized reactance of the capacitance element given by the off capacitance of T is X _N , the dual gate FET 73 and the inductance shunt elements 71, 7
The phase advance amount θ ₄ in the high-pass filter 70 composed of 2 is expressed by the following mathematical formula 4.

[0025]

[Equation 4]

As described above, in the circuit of FIG. 1, the first single-pole double-throw switch 2 and the second single-pole double-throw switch 4 are switched to be supplied to the respective switching signal input terminals 21, 21, 41, 42. By switching according to the signal and selecting either the low-pass filter 60 or the high-pass filter 70, it operates as a high-pass / low-pass type phase shifter for the microwave signal. Further, the bias voltage applied to one of the gate electrodes of the dual gate FETs 63 and 73 is set to a voltage large enough to maintain the dual gate FETs in the pinch-off state, and the other gate electrode is set. By adjusting the applied bias voltage, the effective capacitance value of the dual gate FET can be adjusted, and accordingly, the delay amount or the advance amount of the microwave signal can be adjusted. It goes without saying that the FET used in each single pole double throw switch can be changed to the P channel type.

FIG. 2 shows another embodiment of the present invention in which two single gate FETs are connected in series and used instead of the dual gate FET in FIG. That is, in the embodiment of FIG. 2, the interconnection point of the inductance elements 61 and 62 in the low pass filter 60 and the reference potential point,
For example, two single-gate FETs 66 and 67 that act as capacitance elements are connected in series between the ground potential point and two single-gate FETs that also act as capacitance elements in the high-pass filter 70. The FETs 76 and 77 are connected between the terminals 12 and 32. During operation, the FET 6 in the low pass filter 60
A bias voltage large enough to maintain the FET in the pinch-off state is applied to one of the gate electrodes of 6 and 67, and the bias voltage supplied to the gate electrode of the other FET is adjusted to adjust the capacitance. Adjust the value. Regarding the FETs 76 and 77 in the high-pass filter 70, one FET is kept in the pinch-off state, and the capacitance value is adjusted by adjusting the bias voltage applied to the gate electrode of the other FET.

In the claims, the term "dual gate FET" used in "means for solving the problem", "effect of the invention" and the like is used in the embodiment of FIG. In addition to the original dual gate FET, it also includes two single gate FETs connected in series used in the embodiment of FIG.

[0029]

As described above, according to the microwave phase shifter of the present invention, the bias voltage applied to one gate electrode of the dual gate FET in the low pass filter 60 and the high pass filter 70. The effective capacitance value can be adjusted by adjusting
An effect that the amount of phase delay and the amount of phase advance of the microwave signal can be adjusted by the bias voltage is obtained.

[Brief description of drawings]

FIG. 1 is an equivalent circuit diagram of a first embodiment of a microwave phase shifter of the present invention.

FIG. 2 is an equivalent circuit diagram of a second embodiment of the microwave phase shifter of the present invention.

FIG. 3 is a diagram showing a dual gate FET used in the microwave phase shifter of the present invention and its equivalent circuit.

FIG. 4 is an equivalent circuit diagram of a conventional microwave phase shifter.

[Explanation of symbols]

 2 1st single pole double throw switch 3 Input terminal 4 2nd single pole double throw switch 5 Output terminal 11 1st output terminal 12 2nd output terminal 31 1st input terminal 32 2nd input terminal 60 Low pass Filter 61 Inductance element 62 Inductance element 63 Dual gate FET 70 High pass filter 71 Inductance element 72 Inductance element 73 Dual gate FET

Claims (3)

[Claims] 1. A first and a second inductance element connected in series between a signal input terminal and a signal output terminal, an interconnection point of the first inductance element and the second inductance element, and a reference. It is composed of a low-pass filter consisting of a dual gate FET connected between the potential gate and the dual gate FET, the dual gate FET acts as a capacitance element, and one of the gate electrodes is always in the pinch-off state. A phase retarder characterized by being supplied with a bias voltage of a sufficient magnitude to maintain it and by supplying to the other gate electrode a bias voltage of a magnitude necessary to obtain a capacitance value of a required magnitude. Microwave phase shifter that works as a. 2. A dual gate FET connected between a signal input terminal and a signal output terminal, respectively connected between the signal input terminal and a reference potential point, and between the signal output terminal and a reference potential point. The dual-gate FET functions as a capacitance element, and the dual-gate F is formed on one of the gate electrodes of the high-pass filter including the first and second inductance elements.
A bias voltage of a magnitude sufficient to keep ET always in a pinch-off state is supplied, and a bias voltage of a magnitude necessary to obtain a capacitance value of a required magnitude is supplied to the other gate electrode. A microwave phase shifter that operates as a characteristic phase shifter. 3. A first single pole double throw switch having a signal input terminal and first and second output terminals, and a second single pole having a signal output terminal and first and second input terminals. A double-throw switch, a low-pass filter connected between the first output terminal of the first single-pole double-throw switch and the first input terminal of the second single-pole double-throw switch, and the first single-pole switch. A high pass filter connected between a second output terminal of the pole double throw switch and a second input terminal of the second single pole double throw switch, the low pass filter comprising: First and second inductance elements connected in series between the output terminal and the first input terminal, and a dual gate FET connected between the interconnection point of both inductance elements and the reference potential point
And the high-pass filter has a dual gate FET connected between the second output terminal and the second input terminal, and between the second output terminal and the reference potential point,
It is composed of first and second inductance elements respectively connected between the second input terminal and a reference potential point, and the dual gate FET is always pinched off to one gate electrode of each dual gate FET. A delay voltage characterized by being supplied with a bias voltage of a sufficient magnitude to maintain the gate electrode and a bias voltage of a magnitude required to obtain a capacitance value of a required magnitude on the other gate electrode. -A microwave phase shifter that operates as a phase advancer.